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2626239614
When the kernel crashkernel parameter is specified with just a size, we are supposed to allocate a region from RAM to store the crashkernel. However, MIPS merely reserves physical address zero with no checking that there is even RAM there. Fix this by lifting similar code from x86, importing it to MIPS with the MIPS specific parameters added. In the absence of any platform specific information, we allocate the crashkernel region from the first 512MB of physical memory (limited to CKSEG0 or KSEG0 address range). When X is not specified, crash_base defaults to 0 (crashkernel=YM@XM). E.g. without this patch: The environment as follows: [ 0.000000] MIPS: machine is loongson,loongson64c-4core-ls7a ... [ 0.000000] Kernel command line: root=/dev/sda2 crashkernel=96M ... The warning as follows: [ 0.000000] Invalid memory region reserved for crash kernel And the iomem as follows: 00200000-0effffff : System RAM 00200000-00b47f87 : Kernel code 00b47f88-00dfffff : Kernel data 00e60000-01f73c7f : Kernel bss 1a000000-1bffffff : pci@1a000000 ... With this patch: After increasing crash_base <= 0 handling. And the iomem as follows: 00200000-0effffff : System RAM 00200000-00b47f87 : Kernel code 00b47f88-00dfffff : Kernel data 00e60000-01f73c7f : Kernel bss 04000000-09ffffff : Crash kernel 1a000000-1bffffff : pci@1a000000 ... Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.